Obesity remains a serious health problem and it is no secret that many people want to lose weight. Behavioral economists typically argue that “nudges” help individuals with various decisionmaking flaws to live longer, healthier, and better lives. In an article in the new issue of Regulation, Michael L. Marlow discusses how nudging by government differs from nudging by markets, and explains why market nudging is the more promising avenue for helping citizens to lose weight.

Two long wars, chronic deficits, the financial crisis, the costly drug war, the growth of executive power under Presidents Bush and Obama, and the revelations about NSA abuses, have given rise to a growing libertarian movement in our country – with a greater focus on individual liberty and less government power. David Boaz’s newly released The Libertarian Mind is a comprehensive guide to the history, philosophy, and growth of the libertarian movement, with incisive analyses of today’s most pressing issues and policies.

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Yes, Private Schools Beat Public Schools

How can researchers publish a book concluding that government schools are outperforming private schools despite all the evidence to the contrary? By ignoring all the evidence to the contrary, of course.

Research on this question goes back some 30 years. From James Coleman’s early observational studies of high schools to the experimental voucher evaluations of the past 15 years, researchers have routinely found that similar students do at least as well and, at times, better academically in private schools than in public schools. How have the Lubienskis come up with this surprising finding?

Wolf notes that the Lubienskis ignore numerous performance measures — including graduation rates, college matriculation, future income, parental satisfaction — that give a decided advantage to private schools, even after controlling for student characteristics. They narrowly define performance as math scores on two national tests, ignoring the reading data that also show higher private-school performance.

“School choice programs consistently produce similar or better results for much less money.”

Moreover, both math tests had been altered prior to the Lubienskis’ data collection to more closely align with the way that math is generally taught in government schools as opposed to private schools. By the Lubienskis’ own admission, “the professional development of math teachers changed in the late 1980s to emphasize math reasoning and problem solving and de-emphasize math facts and computations.” Government schools were more likely to embrace the new math curriculum than private schools, which “tended to continue to emphasize traditional math content.” Thus, concludes Wolf, this is a study of “how well private and public school students have learned the brand of math taught in the public schools” rather than a true measure of the differences in math skills.

Wolf also faults the Lubienskis for making apples-to-oranges comparisons of student characteristics that are “measured differently across school sectors” and for methodological flaws in accounting for students who switched from government schools to private schools or vice-versa.

The net effect of these three methodological choices, plus the fact that standardized math results are more closely aligned with how the subject is taught in public than private schools, strongly skew the results in favor of public schools. The beauty of randomized experiments is that their results are not so easily manipulated by bizarre choices of what is controlled. But the Lubienskis don’t like randomized experiments. Advocates for quack medicine also tend not to like randomized experiments. They don’t let you selectively control for things until you get the answer you want.

Furthermore, Wolf’s assessment of the Lubienskis’ methodological flaws leaves aside the question of efficiency (academic achievement per dollar spent per pupil). Efficiency is an issue that apologists for the status quo prefer to avoid. For example, school-choice critics pooh-pooh results from the over-regulated Milwaukee voucher program because test scores of choice students were not significantly different from government school students (setting aside the choice students’ significantly higher levels of high-school graduation and college matriculation). However, the critics neglect to mention that the private schools achieved those results at about half the cost per pupil.

School choice programs consistently produce similar or better results for much less money. Indeed, in a 2009 review of the global research literature, the Cato Institute’s Andrew Coulson found that every study to measure efficiency in education returned a statistically significant positive result for markets.